building specs for the 6.9L

[bronco78idi]

Hi all,
I have been researching over the last 6 month reading and adding info on how to build a 6.9L with a turbo. I have found great info but it always lacks the detail of spec and parts name of manufacture used.
My engine is at a machine shop here is what I am having done but I put it on hold for now while I find some answers to the following questions. My use Daily driver and off road fun. Any help on this would be great. This is my first Diesel.

1. Valve job
2. Deck the block true
3. Line bore the crank to cam
4. Balance the block

Question I am looking of help on.

Lower end Questions

Can you find 6.9l rods with larger wrist pin like the 7.3?
What is the best manufactured Piston to use?
Should I shave piston down the piston to 19.5:1 or 20.5:1 to get more boost from the turbo I am adding?
Would you stud the lower end?
Is there an oil pump that pushes more volume? and what is the best manufacture to use?

Heads.
I have already had the valve job done, but now I am thinking I should have then tear it down again.

Should I have used 7.3L Exhaust Vales? And what is the size difference. I also was reading about using 60lb springs and retainers. But they never said who made them.
I am already using the 7.3L Rockers and assembly and ARP Stud KIT, am I missing anything more?

 

[icanfixall]

Well lets answer the simple questions. All idi rods will fit any idi engine be it a 6.9 or 7.3. Now about a big pin rod in a 6.9... Nope. Wont work unless you have custom pistons made. No stock supplier for turbo pistons for the 6.9. That used to be an option but no longer possible. Balance the block... No but make sure you balance the complete rotating parts of the engine. 7.3 exhaust valves in a 6.9... No need. You already have them in the 6.9. All 6.9 and 7.3 non turbo valves are the same part. Only differance is the turbo exhaust valves nade of inconel material. They are expensive too. 60 lbs springs makes no sence to me. All 6.9 and 7.3 engines have the same springs be it intake or exhaust or turbo application. There is no aftermarket high volume oil pump. We already have one as a stock application and it works great. The best piston is what came originally in these engines and over the years they have been upgraded plenty. They are the Mahle pistons. Milling 14 or 15 thousands off the tops is ok but any more and you get the top ring too close to the heat and it will fail. I got that info from Eric who at the time was working as an engineer for mahle. Studding the bottom end is not needed. Its plenty strong to hamdle what we ask of it. Really only 2 members have pushed the crank out the bottom of these engines. They were making 1000+ hp. So we don't really worry bout that. Yes, line bore the mains and beck the block. Doing this will reduce the drag on the crank and decking the block makes all the pistons the same height in the bores.

 

[xcite]

balance rotating assembly
no need to decompression unless using custom turbo system
aftermarket cam either J2(higher reving) or Type4(low end grunt)
valve springs that give about 100 lb open cant remember the part number right now.
new roller lifters(best quality you can get not bushed)
No need to stud bottom end unless like above custom turbo system
there is a best piston in my mind just cant remember maker right now will look into it for you.
Use the best exhaust valves you can find they are worth it in the end.
Have machine shop keep tolerences on the tighter part of spec and oil pressure will be better longer.
Tri coat pistons will add to longevity as well as anti friction coatings.

 

[NTOLERANCE]

Have machine shop keep tolerences on the tighter part of spec and oil pressure will be better longer.
.

Tell the machine shop its not a small block chevy. Or it will end up a rattling mess.

 

[xcite]

balance rotating assembly
no need to decompression unless using custom turbo system
aftermarket cam either J2(higher reving) or Type4(low end grunt)
valve springs that give about 100 lb open cant remember the part number right now.
new roller lifters(best quality you can get not bushed)
No need to stud bottom end unless like above custom turbo system
there is a best piston in my mind just cant remember maker right now will look into it for you.
Use the best exhaust valves you can find they are worth it in the end.
Have machine shop keep tolerences on the tighter part of spec and oil pressure will be better longer.
Tri coat pistons will add to longevity as well as anti friction coatings.

Comp 910 springs are what you want.
silvolite's are the pistons you want, and YES they are a "turbo" piston for a 6.9

 

[88 Ford]

You are right about the Comp 910s but are you positive about the KB Silvolites being a turbo piston? If they are, they will fit a turbo engine rod. The turbo rods are a bit stronger...

 

[88 Ford]

Also Bronco78, what are your power goals for the engine and what turbo are you planning on using?

 

[Knuckledragger]

Balance the block? I have built a bunch of engines in my time and this is the very first time I have ever heard the term. If it has a real purpose, I fail to discern it. Can you enlighten us?

About machining the block - make sure you warn the machine shop that the blocks have a high nickle content and are pretty tough to machine compared to a SBC. They need to use new, or at least sharp, tooling.

 

[icanfixall]

The above posting about machining these high nickle blocks is so true. Speed up the cut and the tool chatters ruining the finish. Use an old or dull tool and its ruined again. The speed and feed of the cut needs to be slowed down. That takes more time and time is money in a tight profit margin shop.

 

[Dieselcrawler]

Also rear up in our freeze plugs if the shop took them out. Oil squirters too.

 

[bronco78idi]

Hi all

Thanks for the input so far. I am having the running parts balanced. crank, rods etc. just used the word balance the block as a general term.

I am looking for a solid running engune. I am not looking to get crazy. something that will move me along the trails and daily driver with better fuel milage then the 351M. The 351 was fine on the trails, but climbing hills on the highway or steep grade I alway had to down shift to 3rd. low and slow no problem. Plus I live in a state that HATES ALL TRUCKS or anything for that matter. I want to dump smog check. and a 2bbl carb.

I am not sure what turbo to get yet. I am still trying to figure out the engine. I have been a gasser all my life and the diesel is so different in building.

Thanks all

 

[88 Ford]

Are you looking at doing a custom turbo for sure then? Cus with a turbo from either Banks, Hypermax, and ATS you are looking at about 210hp/450tq max with those turbos and an upgraded fuel system. If you want slightly more than that, you will definitely need to upgrade. Also have you thought about a cam upgrade? There are a few good cams around now. Where you are wanting power though, the Typ4 cam might be what you want. The other one is built more for topend horsepower.

 

[bronco78idi]

Hey all,

Went to the rebuilder today and drop another 400.00 on the account. I know that’s not much. I am already into this build for 3K and plan to finish the engine around 6K The owner is on vacation so I talked to his stand in. told him I want this engine to stay within close tolerances to spec and take their time on the block. I figure the pistons to use is the Seal Power Speed-Pro Hypereutectic Piston. Here is the link. Any comments before I order them http://www.summitracing.com/parts/SLP-WH729CP30/

I am not using any of the old parts, less the block, crank, rods, heads and intake.

Here is what I have done so far with the engine

I deburred the engine before I took it to the shop.
Engine and heads hot tanked
Mag Block and heads came out Great. One small crack on an exhaust seat repaired
Valve job is done, All new Spring, Valves, Liners, retainers, new 7.3 Rockers.
New lifers and set of push rods.
ARP Stud Kit.

Next Step to be done

Order Pistons and Ring set with the Engine kit complete less CAM
Have engine cylinders sized for Pistons
Have Compression dropped from 20.7:1 to 18.5:1 (any commits on this? Idea is little more boost)
Thinking of sending pistons to be coated(any Commits?)
Balance the assembly
Any thoughts on an external oil cooler?

Once the above is done

Figure the grind for the cam that will work for my application
have long block assembled.

I am looking for the best pump and injectors for this build. What would you buy?

I am not sure about the Turbo yet that is far down the build yet. Just like the innercooler.

Thanks again for all the help!

 

[xcite]

I would still recomend silvolite pistons they have a much better alloy they are made out of, and a tri-coat on them will make them even tougher.
I would highly recomend updating the cam at this time to something more turbo friendly. One from typ4 on this forum for lower rpm torque, or a J2 cam for higher reving. Depending on cam regrind may need longer pushrods.
I wouldnt decompression the engine unless you are planning on making your oun custom turbo system. The standard bolt on turbo kits for these engines will not work very well with a decompressed engine. To do anything to the pistons you need to know what you are going to do for turbo, bolt on kit or custom setup, this is one item you really have to plan ahead for.
I would leave the oil cooler alone, but remote mounted oil filtering could be a big plus.
Frost plugs on these engines can be a pain, make sure they are stainless steel or go all out and tap for pipe plugs and problems are over.
When putting finishing touches on engine go with a turbo cal pump or moose pump for better fueling.
Definetly plan on an intercooler when completing the project it will be well worth the effort.

 

[88 Ford]

Something else I would strongly recommend is to cryo treat all the internals. That will add even more strength and rigidity to them. It would also help with heat resistance too. There is a thread I posted about cryo treating a few days ago. Look it up. It has a good link in it. Also I would definitely coat the pistons too.

As for the pistons, I really don't think those pistons will handle the heat of an IDI very well. I would at a minimum get the pistons from Mahle. And as for the compression drop, there is a guy on another site running 18.5:1 and is pushing 36psi into it. The last dyno before he added more fuel and changed his turbo he dynoed at 292/614. He is a bit higher than that now.